Method of regulating furnaces.



PATENTBD JULY 1 -E. 'M oLEAN METHOD OF REGULATING'FURNAGE$.

APPLIOATION FILED MAY 6, 1905.

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wmvassgw 7 "APATBNTED JULY 17, 19136 v E. MoLEAN. METHOD OF'I-REGULATING FURNACES.

APPLICATION FILED MAY6,1905.

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M/l/E/VTOR B fiz ATTOR/VEVJ WITNESSES No.'82e,349. PATENTED JULY 17, 1906.

y EL MULEAN. 3 METHOD OF RBGULATING FURNACES.

' APPLIOATION FILED MAY 6, l905.

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QW/TNESSES:

NT R QM ATTORNEY PATENTED JULY 17,1906. E. MGLBAN. ETHOD OF REGULATING FURNACES.

APPLICATION FILED MAY 6.1905.

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UNITED sr-Arns;

PATENT OFFICE.

EMBUKY MGLEAN, ()F'NEW YORK, N. Y.

METHOD OF. REGULATING FURNACES.

Specification of Letters Patent.

Patented July 17, 1906.

Original application filed May 23, 1904, Serial No. 209,256. Divided and this application filed May 6,1905. Serial No. 259,241.

' citizen olthc United States, and a resident of the city of New York, borough of Brooklyn in. the county of Kingsand State of New York, haveinvented certain new and useful Improvements in Methods of Regulating I urnaces'. of which thefollowing is a specification.

This invention relates toa novel and i1nv proved method of regulating furnaces and is a'di'vision of my pending application, Serial No. 209,256.

My invention consists in the method set forth in and fallingwithin the scope of the appended claims.

In order that my method ma be readily understood by those skilled in,the art to. which it appertains, I have shown in the accompanying drawings one form of apparatus through the agency of which it may be caris a view at the left hand side of the apparatus' shown by Fig. 4. Fig. 6 is a Nertical longitudinal sectionsiinilar to Fig. 1, showing a i'noditication of the general organisation. Figs. 7, S. and 9 show diagrammatically the position of the damper, the damper-inotoij and the blower-engine regulating-valve at the condition of starting bel'ore there is steam in the boiler, the condition ol running below normal stcam-pressure, and the'condition of running-above normal StGfilllfllKQSSUl-G, re

spcctivel v. w

'ith the apparatus illustrated my improved method is accomplished by regulating. the outlet for productsof combustion correspondingly with and 'connnensurate to the regulation of the forced d'raftwith gradu ated rate of combustion between the extremes. It will be readily understood that the method may be practiced in various ways or by-the utilization of various kinds of apparatus and'is applicable to furnaces for various purposes.

The present inven-tion ha s in view to maintain substantially uniform steam-pressure with maximum economy of coal consumption and minimum liability of injury to the boiler by inrllshof cold air when the firebox is opened and of dilution and cooling of the gases by air drawn in through crevices in the door or furnace setting- This is accomplished by maintaining in the fire-box a pressure equal or substantially equal to the atmospheric pressure in the boiler room, while at thesame time supplying to the fire-box the fu-llamount of air required for ell'ective combustion of the fuel. Under these conditions when the door of the fire-box is opened there is an absence of inward or outward draft, ,as

may be readily determined by suspending av light cloth across the open door.

One organization that experience. has den) onstrated to be effective in producing autoQ matically the conditions described comprises a draftblower and a cooperating stacl damper both controlled livtlie steam-pressure in such way that a comparatively minute reduction of pressure causes a corresponding acceleration of the speed of the. blower and increase of volume of air supplied to the fire-box by the blower and an actuation of the damper to afl'ord a corresponding increase of the stack-outlet, area commensu rate with the increased air-delivery from the blowerthat is to say, there is in the operation of this system minute or gradual changes of the position of the damper corresponding to variations or speed of the blower. In this way the steam-pressure may be held at a substantially uniform point, and the pressure within the fire-box may exactly or substantially balance atmospheric pressure in the boiler-room, so that on the opening of the.

lire-box door there will be no inrush of the cold air with the usual accompanving bgnler contractlon. In the particular organization shown steam from the boiler is passed through a regulating-Yalve, from whence it passes to the blowerengine and to a -diaphragm-motor having the characteristic operation hereinafter described. Another way of practicing my method is to operate the blower at uniform or substantially uniform speed and throttle the air-supply passing therefrom to the fire-box. g

In Fig. l 'a draft-blower a is driven by an engine I), supplied by steam from the boiler through pipe connection 0, which contains steamcocks d and (Z and between them a steam-regulating valve f and also has applied to it a steam-gage 9, beyond which one end ofzthe piston-rod r is engaged by knifeedge r carried by the lever r.

The diaphragm-motor 7c is or may be of any suitable ordinary type; but the lever r thereof is controlled, as hereinafter described, relatively to the steam-pressure exerted upon the diaphragm of the motor that is to say, its me vem'ent is a graduated one between its two extreme positions, one being the closed position in which the damper may be entirely closed or only partly closed, according to the s ecial requirements in any given 'case, and tile other the open osition in which the damper may be entire y or only partly open, or the lever'of the damper-motor may be so controlled that the changes in the position of the damper occur as a series of relatively minute steps or increments of movement either from theppen orclosed position of the damper, as the case'may be.

Around the parts (1 d f g is a shunt or bypass pipe connection 8, containing an ordinary steam-cock s", which may be opened in starting to allow steam at full boiler-pressure to pass to the blower-engine, as well as to the lower side of the diaphragm of the dam ermotor 7c, and thereby cause the opening 0 the damper.

Steam from the boiler enters the regulating-valve f, as indicated by the arrow, Fig. 2,

' and passes by opening f to the under side of a diaphragm f which is normally urged downwardly by a spring f adjusted by screw-bolt ff and carries a valvespindle, with two valves f 5 seating in the same direction upon two valve-seats, through which steam from the boiler passes. The steamoutlet. side of the regulating-valve is connected by an opening f 6 with the steam-inlet side. The opening f is of such capacity as to deliver a. determined quantity of steam when steam from the boiler is at a given pressure. Thus if the valves f 5 be seated a volume of steam, determined by the capacity of sess le opening f ,will pass to the blower engine, cans ing the blower to operate at minimum speed and to the under side of the dampermotor, causing minimum opening of the damper. This condition of course only occurs when the boiler-pressure is at a maximum. As the boilr-pressure falls the diaphragm f 2 moving downward opens the valves f", permitting additional steam to pass to the blower-engine and damper-motor and causing increase of speed of the blower and a corresponding extent of opening (or increase of opening) of'the damper. A further fall of steam-pressure produces a corresponding further opening of valves f resulting in corresponding further increase of speedof blower and opening of damper. verse conditions are brought about. In other words, the increase or decrease of blower speed and corresponding damper-opening As steam-pressure increases re' correspond to variations of boileripnessure,

and the changes occur on "such minute changes of boiler-pressure that the latter is maintained substantially uniform. Since in any boiler which is to be worked at a given pressure the required amount of'air and the required stack capacity to carry ofi'the products of combustion at the various possible speeds of the blower may readily be arrived at, the pressure of gasesin the fire-box and of air in the boiler-room may be equal or sub stantially so, and when the fire-door is opened there will be, therefore, no inrush of cold air to lowerthe temperature of the furnac e and injure the boiler. As the boilerpressure and blower speed vary, the damperopening correspondingly varies, the opening being increasedin one case-to carry off the increased volume of gases without material increase of pressure in the fire-box and in the other decreased to prevent material reduction of pressure in the fire-box. Such retardation of gas and products of combustion by this action of the damper allows time for intimate mixture of the heated air with'th'e gases, insuring, substantially complete combustion and a substantially smokeless stack. boiler is properly proportioned for the work I it has to do, there is also a maximum absorption by the boiler of heat from the gases, so that the temperature of the stack may be very little above the temperature of the boiler.

The described control of the lever-arm r of the dam er-motor may be accomplished by means of a suitably-constructed coiled spring a of such character and dimensions that the strength of its reaction through the entire required range of its distention shall in cooperation with the regulated steam-pressure beneath the diaphragm of its motor result in the graduated or gradual changes of position of the damper, as already described. Like results may approximately be effected by the'arrangement of weights shown in Figs.

If the 4and 5. A pendent rod u, pivoted upon the end of the lever 1, passes through a series of weights u v 'r" r r, (of whiclnhowever, there and the rod u is headed at its lower end, so

that as the lever is moved upwardly by the strain. of the damper-motor the weights to, if, U2, 1;, and-v are picked up in succession, c'orres ending positions of the damper pbeing in icated by the dotted lines on Fig. 4, as they are also indicated by the dotted lines in Fig. 3, wherein in lieu of the series of blocks.

of different weight the spring t above described is employed. To locate the brackets and adjust the weights shown in Fi s. 4 and 5 to assist in maintaining constantIy atmosph eric pressurein' the fire-box, the following method may be employed' Let the blower be-run at minimum speed and by hand adjust the damper 'intil atmospheric pressure in the fire-box is attained... This may be determined by suspending a sheet of light material in front of the open [11II 1&C8 d001.. The position of the lower end. of the rod ct is then noted, and the weight'required to hold the damper stationary in that position ascer-' osition of the.

tained. This determines the lowest bracket and the require amount of the weight 1) resting thereon. 'Next, let the blower be run at maximum speed and by hand. adjust the damper until a'tmos )heric pressure in the fire-box is attained. T e po-, sition of the lower end of the'rod uis then noted and the weight required to hold the damper stationary in that position ascer-' tained. This determines the position of the uppermost bracket and the required aggregate amount ot the weights 0 t v c '0 Next repeat these proceedings with as many intermediate speeds of the blower as desired, thereby. determining the positions ofthe intermediate brackets and the weights to be carried thereby. ratus may be adjusted so that substantially .constant atmospheric pressure willbe main of the \blower.

Theoretically and practically the best results are obtained by supplying-to-the fire 7 box sufiicient air for perfect combustion and maintaining a balance, or substantially so,

between the pressures in the fire-box and boiler-room. .The apparatus may, however,

be so adjusted that any desired substantially uniform pressure below that of" the boilerroom'may be. maintained. This may be .de-

sired in semi-(gases for the purpose of ven-' By this means the appa-' tained in the fire-box for all Working speeds.

the boiler by pi e w, through the regulatingvalve f, and t ence by pipe at to the dia phr'agm-motor 7c of the stack and by pipe 1 to a diaph ragm-motor 2, controlling a damper 2 in the air-duct 112-, through which air passes from the blower to the ash-pit. Both these dam ermotors are controlled by springs or weig ts in the manner already described. The blower-engine, however, is connected direct to the boiler and runs, therefore, at a substantially uniform speed,' the quantity of steam admitted thereto being fixed by setting the hand-operated valve 3.

I am aware that heretofore systems of-- boiler regulation in some respects resembling that herein disclosed have been proposed.

' In such systems, however, while the blowerengine has been controlled to control the blower relatively to the steam-pressure of the boiler the stack-damper has been so constructed and operated as to have really but two positions, one open and the other closed' that is to say, on a riseof pressureabove norblower, slow downuntil a condition is establishcd resulting in-the increased speed of the blower, accompanied by full opening of the damper. vantages and being comparatively etlicient, affording an economy in coal consumption not obtained in unregulated boilers, neverliable expulsion of the gases from the fire-box into the boiler-room when the blower speed is increased and before the damper opens, and also 'tend at times when the damper is' open'tocause a reduction of pressure in the fire-bo below that of the boiler-room atmosphere, causing inrush of a large quantity of cold air should the furnace-door beopened.

Instead of a blower-engine actuatedby the blower may 'be of a difierent character power. For instance, an electric motor could rheostat be controlled by a governing motor In Figs. 7, 8, and 9 I have shown diasitions which they occupy, respectively, first, when the fire is starting and there is no steam on-the boiler second, when the presthird, when the pressure in the boiler is above the normal. shows the parts when the fire is starting and there is no steam on the'boiler, it'will be observed that the damperp 1s wide open, soas It is shown as held open in this case by a hook i 10, for which of course any suitable device and may be actuated from another source of;

such, for instance, as the'damper-motor k or 2.

to allow the fire to start under natural draft.'

mal the staclt-dampeitljvill close: and the Such systems while having. ad-

theless necessarily permit of a somewhat j marked variation of boiler-pressure,render ,lOO

steam from the boiler the motor or engine of I be used, the speed of which may be controlled by a rheostat and the contact device of the grammatically the damper p, the dampermotor k, and the regulating-valve in the po- I Z Ov sure in the boiler is below the normal, and,

Thus, referring'to Fig. 7, which I performing the function may The damper-motor 7c is then performing no function, while the regulating-valvefis wide open (there boing'no pressure under the diaphragm) and. ready to admit a free passage of steam when it is generated to the blowerengine. Fig. 8 shows the position of the parts when the. pressure in the boiler is so far below normal that the speed of the blower is at its maximum, the damper-motor being brought In this case the'increased pressure underthe diaphragm of the regulating-valve f almost closes the passage through the regulatingvalve, reducing, on the one hand, the amount apf steam admitted to the blower-engine to -the minimum and, on the other hand, reduc-, v in'g'""the pressure under the diaphragm of damper-motor 7c sufficiently to bring the damper p to the position where it. will balance the draft at this speed of the blower.

' the limits there shown, so

'At intermediate steam-pressures, as will be readilyunderstood, the positions of the parts shown in Figs. 8 and 9 will be simultaneously and correspondingly varied between that the pressure in theflip-chamber will always be maintained su stanti'ally'constant and preferably e ual to the pressure of the atmoshpere. f

Where'ffhave employed the term blower I .intend the same to include any apparatus for supplying air'to the furnace at a pressure above atmospheric ressure. Instead of automatically icontro 'ng-the volume of air supplied-Ito'j and the volume of gases discharged from the'furnace by the steam-pressure or other function of the furnace it is obvious that one of these may be controlled by be substituted. hand or in any other steam-pressure) provided the other is simultaneously controlled correspondingly by any suitable means, so as to maintain a substantially uniform pressure in the furnace under varying rates of combustion, as already described.

I do not claim in this application the appamanner (including 'ratus described herein, as the same forms the Y subject-matter of and is claimed in my Patent No. 817,438, patented April 10, 1906, and of which this application is a division.

Having thusdescribed my invention, what I claim as new, and desire to secureby Letters Patent, is

1. The method of regulating furnaces consists in maintaining in the furnacechamber a substantially uniform pressure under varying rates of combustion.

2. The method of regulating furnaces which consists in maintaining in the furnacechamber a pressure substantially equal to atmospheric pressure under varying rates of combustion.

3. The method of regulating furnaces,

whichconsists in supplying air to the furnace at different rates of delivery and simulta: ne'ouslydischargin'g gases from the furnace 1n quantities proportioned to said differenti'ates of delivery, whereby a substantially uniform pressure is maintained in the furnace under varying rates of combustion.

4. The method of regulating furnaces, which consists in supplying air to the furnace at a pressureabove that of the atmosphere and at different rates of delivery and simul taneously discharging gases from the furnace in quantities proportioned to said'diflerent rates of delivery, whereby a substantially uniform pressure is maintained in the furnace under varying rates of combustion.

In testimony whereof I, have signed my name to this specification in the presence of two subscribing witnesses.

EMBURY McLEAN.

Vitnesses R. B. CAVANAGH, C. J, RATHJEN. 

